Lacrimal bicanalicular stents may be used to stent the punctum and canaliculus for conditions that cause punctal and canalicular stenosis.
Many ophthalmic and systemic conditions can cause stenosis and closure of the punctum and canaliculus, causing patients to have chronic tearing which can cause irritation and decreased visual acuity. These conditions can include congenital conditions, infection, inflammation, chemotherapy and trauma. Current treatments for stenosis and closure of the punctum and canaliculus involve stenting the nasal lacrimal duct system with either a bicanaliculus stent that goes down into the nose or a self retaining bicanaliculear stent that sits in the nasal lacrimal sac. A third possibility is a monocanalicular stent that either sits in the upper or lower punctum and canaliculus and goes into the nasal lacrimal sac or into the nasal cavity. Each of these stents has specific disadvantages.
Current bicanalicular stents have to be placed in an operating room with the patient under anesthesia. This type of stent has to be passed into the nose and retrieved out of the nose. It can be very difficult to locate and retrieve the stent out of the nasal cavity. The process of placing such a stent can have complications such as nose bleeds and complications due to anesthesia. Also, anchoring the stents so they do not dislodge is complicated, and often the stents will dislodge.
Monocanalicular stents may be placed under local anesthesia, but it is very hard to determine where the distal end of the stent sits within the lacrimal system. The stent, which has a collarette, also sits in the punctum and occludes tears from draining into the lacrimal system, which causes constant tearing while the stent is in place. These stents also have a tendency to be dislodged. Furthermore, monocanalicular stents only treat one of the nasal lacrimal drainage systems, either the upper or lower system, but not both.
The vast majority of eye medication is delivered via liquid drops by a conventional eye dropper. While this delivery mechanism has proven effective, it also has several drawbacks. For example, much of the medication runs off the eye before it can be absorbed or penetrate into the eye. Further, the medication is not applied uniformly over time in that there is an initial higher concentration of drug immediately upon application, as compared to subsequent time periods. Finally, patients often forget to use their medication, or are incapable of properly administering the drops for themselves. In other words, it is not uncommon for patients to fail to medicate themselves sufficiently, or at the correct times.